Mud saver for drilling rigs

ABSTRACT

Apparatus is disclosed for attaching to the lower end of the kelly of a drilling rig to keep the drilling mud that is in the kelly from running out, when the kelly is disconnected from a drill string for any reason, e.g., to add another joint of pipe to the string. The mud saver includes a two-piece tubular housing for connection to the lower end of the kelly, between the kelly and the upper end of a string of drill pipe. An elongated sleeve of resilient elastomeric material is located in the housing with its upstream end clamped open between the two sections of the housing so all the mud pumped through the kelly into the drill pipe will pass through the sleeve. The downstream end of the sleeve is held closed by two springs located on opposite sides of the sleeve. These springs exert only enough force on the lower end of the sleeve to hold it closed against the hydrostatic pressure of the drilling mud above the sleeve when the kelly is disconnected from the drill string to thereby keep the mud in the kelly from flowing out its lower end. When the kelly and mud saver are reconnected in the drill string, drilling mud can be pumped down the kelly, through the sleeve, and into the drill string, and the pressure of the mud is more than sufficient to force the lower end of the sleeve open to permit the mud to flow through.

United States Patent Charles S. Livingston [72] Inventor Houston, Tex.

[21] Appl. No. 681,698

[22] Filed Nov. 9, 1967 [45] Patented Mar. 2, 1971 [73] Assignee James B. Ringgold Houston, Tex. a fractional part interest [54] MUD SAVER FOR DRILLING RIGS 525, 525.1; 222/490; 166/225,224; l28/(Bag Digest); 175/218 [56] References Cited UNITED STATES PATENTS 2,278,780 4/1942 Harrington 175/218 2,328,948 9/1943 Bourke 137/525.l 3,331,385 7/1967 Taylor 175/218 Primary Examiner-Alan Cohan Attorneyl-1yer, Eickenroht, Thompson & Turner ABSTRACT: Apparatus is disclosed for attaching to the lower end of the kelly of a drilling rig to keep the drilling mud that is in the kelly from running out, when the kelly is disconnected from a drill string for any reason, e.g., to add another joint of pipe to the string. The mud saver includes a two-piece tubular housing for connection to the lower end of the kelly, between the kelly and the upper end of a string of drill pipe. An elongated sleeve of resilient elastomeric material is located in the housing with its upstream end clamped open between the two sections of the housing so all the mud pumped through the kelly into the drill pipe will pass through the sleeve. The downstream end of the sleeve is held closed by two springs located on opposite sides of the sleeve. These springs exert only enough force on the lower end of the sleeve to hold it closed against the hydrostatic pressure of the drilling mud above the sleeve when the kelly is disconnected from the drill string to thereby keep the mud in the kelly from flowing out its lower end. When the kelly and mud saver are reconnected in the drill string, drilling mud can be pumped down the kelly, through the sleeve, and into the drill string, and the pressure of the mud is more than sufficient to force the lower end of the sleeve open to permit the mud to flow through.

PATENTEU MAR 2 l97l sum 2 BF 2 CHARLES S. LIVINGSTON INVENTOR.

4 TTORNE Y5 MUD-SAVER FOR DRILLING RIGS This invention relates to apparatus for reducing the drilling is connected to the drill pipe through a kelly, which isrotated by a rotary table.

When another joint of pipe is tobe added to the drill: string or the pip'e'is to be pulled from the hole, thekelly is disconnected from I. the pipe string. When this occurs, any mud. remaining in the kelly willrun out and be wasted. Drilling-mud usually contains a mixture of chemicals, someof which are very expensive. In addition, when the: mud flows outof the kelly onto the floor of the drilling rig, thefloor becomes slick and unsafe for the workmen. Also, the mud is often strongly basic and harmful to workmen s skin-and clothing.

The amount of mud lost each timethekelly is unscrewed from or broken out of the string can be reduced by waiting as long as possibleafter the pumps are shut down and the kelly pulled back up into the derrick. For if the density of the mud in the drill pipe and the mud outside the drill pipe in the annulus is the same, the level of the. mud in the pipe'will drop to. that of the mud in the annulus. This requires time, however, and drilling rig time is very expensivexFurther, thedensityr of the mud in the kelly is often less than that of the mud in'the an.- nulus for various reasons such as the addition of. water to the mud before it is pumped back into the well bore. When this condition exists, the mud level in the drilling string, which includes the kelly and the pipe string, .will not fall to the levelof the mudinthe annulus.

Therefore, it isan object of this invention to providelapa paratus to keep the mud'in a kelly from running-out its lower end when the kelly is disconnected from a pipe string; '1

The apparatus includes tubular housing 12, which is made up of two sections, 12aand 122). Section 12a is connected to the lower end of kelly 10 and the lower. end of section 125 is connected to drill pipe 11. Thus, the housing may also serve ,as

a kelly saver sub since, when breaking the connection between the kelly and the drillstring, the connection between housing section 1211 and drillpipe 11 will be the one that is broken. An

additional kelly saver sub can be employed if desired between the lower end of housing section 12b and the drill pipe.

Located'in housing 12 is valveelement assembly 13. It includes elongated sleeve 14. The sleeve, preferably, is made of an elastomer, such as natural or. synthetic. rubber. Also, the sleeve may be reinforced, as by layer 15 of cotton duck. The sleeve is molded with a cylindrical opening in its upper end l4a. The opening tapers down to elongated slot 17 through lower end 14b of the sleeve. The wall thickness of the sleeve is substantially uniform throughout. Its exterior configuration is as shown in thedrawings; a cylindrical shape at its upperend and flat-sided across its lower end. Thiscan best beseen in FIGS. 4 and 5.

Means are provided to mount the sleeve in housing 12 with its upper end 14a held opensoall fluid pumped through the kelly and housing l2=into the drill string will pass through the sleeve. In the embodimentshown, mountingring 16 encircles upper end 14a. Preferably, the ring 'isbonded to the sleeve when the sleeve is molded. To improve the attachment between the elastomeric material of the sleeve and mounting ring 16, annular groove l8 is provided in the exterior of the ring. A plurality of spaced holes 20 extend through the mounting ring and intersect groove 18. This allows the elastomeric material of the sleeve to flow through openings20 during the It is another object of this invention to provide apparatus cal section, of the mud saver apparatusof this invention in stalled in a pipe string;

FIG. 2 is a sectional view taken along line 2-2 of FIG. 1; FIG. 3 is a view on an enlarged scaleof the portion of FIG. 1 within the circle 3;

FIG. 4 is a view, on an enlarged scale,-looking upstreamat the valve element assembly of the mud saving. apparatus of FIG. l;and

FIG. 5 is a cross-sectional view taken along line 5-5 of FIG. 4.

The invention is shown in the. drawings and will be described as used with a conventional;kelly. The apparatus of the invention may have utility, however, where a power swivel is employed and a conventional square or hex-type kelly joint is not employed. Therefore, kelly, as referred to herein and in the claims, is intended to include the connection between a power swivel and the apparatus of this invention, which will be locatedtbetween the power. swivel and-the drill pipe. The mud saving apparatus of this invention, as shown in FIG. 1, is installed. between kelly 10. and pipe joint 11..Pipe

joint'll is the top joint in the pipestring (not shown) that extends downwardlyinto the well bore.

molding operation and fill. up both the openings and annular. groove 18 to provide a mechanical bond between the mount- .ing ring and the sleeve.

Mounting ring 16 and, consequently, sleeve 14 is fixed an held in position in housing 12 by housing sections 12a and 1212. These twosections are connected together by threaded connection 22. Before this connection is madeup, sleeve 14 is positionedin housingsection 12b with mounting ring 16 resting on upwardly facing annular shoulder 28 on housing section 12b. The two housing sections are screwed together until lower end 26 of section 12a engages the mounting ring suffi i ciently to firmly hold mounting ring 16 between the lower end of housing section 12a and upwardly facing shoulder 28. The;

Means are provided to resiliently urge the lower end of the sleeve closed with sufficientforce to hold it closed against the hydrostatic head of the fluid in the kelly, when the-kelly and. housing are disconnected from the drill pipe. In the embodiv ment shown, leaf springs 34 and 36 are provided for this .pur-

pose. As best seen in FIGS..2 and 4, the lower ends of the springsengage opposite sides of the slotted lower end of the sleeve and urge slot 17 closed. The'lower ends of the springs are trifurcated, each having three fingers to engage the lower slotted-end of the sleeve and spread the force exerted by the springs over substantially the length of the .slot. In the drawings, slbtl7is shown open slightly even though springs 34 and 36 are in position to hold it closed. This was done to make the locationand shape ofthe slot clear in the drawings.

- The upper ends of the springs are attached to mounting ring 16..The connection between the springs and the mounting ring is best seen in F I65. 3 and 5. Both springs are connected in the same manner, so only the connection between spring:36 and the mounting ring will be described in detail. The mounting; ringlis provided withverticalslot 40 into which the upper end. of spring ,36 extends. The. spring. has two vertically spaced mounting holes 37, which are in alignment with two vertically spaced tapped holes 38 in mounting ring 18. Mounting screws 42 extend through mounting holes 37 in the springs and threadedly engage the tapped holes in the mounting ring to attach the upper end of the spring to the mounting ring. The upper end of spring 34 is mounted in the same way in a slot in the mounting ring located diametrically opposite to slot 40.

The springs are designed to exert just enough force to hold the lower end of the sleeve closed against the hydrostatic pressure of the fluid that will exist in the kelly when the pumps are shut down preparatory to making a connection. Thus, the springs will exert little resistance to the forcing open of the lower end of the sleeve by the mud during normal circulating conditions. They will quickly close the lower end of the sleeve, however, as soon as circulation stops so that the kelly can be broken out of the drill string without delay and without the danger of losing any of the fluid still remaining in the kelly at the time circulation is stopped. 7

From the foregoing, it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth, together with other advantages which are obvious and which are inherent to the apparatus and structure.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.

As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

lclaim:

1. In a drilling string through which drilling mud is pumped downwardly into a well bore including a plurality of pipe sections connected together with screw threads and a kelly connected to the upper end of the pipe string, the improvement in combination therewith of means for holding most of the drilling fluid in the kelly when the kelly is disconnected from the upper end of the pipe string, said means comprising a tubular housing connected in the drilling string between the bottom of the kelly and the top of the pipe sections and a valve element assembly located in the housing including an elongated sleeve of resilient elastomer material, means mounting the sleeve in the housing with its upper end held open so that drilling mud, as it is pumped downwardly through the kelly into the pipe sections below, will flow into the upper end of the sleeve, pass downwardly through the sleeve, and out the lower end of the sleeve, and means resiliently urging the lower end of the sleeve closed with sufficient force to hold the lower end closed against the hydrostatic head of the drilling mud in the kelly when the kelly and housing are disconnected from the pipe sections to keep the mud in the kelly from running out its lower end but which will allow the lower end of the sleeve to be forced open by pump pressure to permit normal circulation of mud to be maintained through the drilling string during drilling operations.

2.The mud saver apparatus of claim 1 in which the housing includes an upper and a lower section and the sleeve mounting means includes an annular member attached to the upper end of the sleeve to hold it open, said member being clamped between the upper and lower sections of the housing to hold the sleeve in place in the housing with its upper end held open by the annular member.

3. The mud saver apparatus of claim 2 in which the resilient means includes two elongated springs positioned on opposite sides of the sleeve, each spring having one end connected to the annular member and the other end engaging the lower end of the sleeve on the opposite side thereof from the other spring.

4. The mud saver apparatus of claim 3 in which the lower end of the sleeve is flat when closed.

5. The mud saver apparatus of claim 4 in which the springs are made of flat spring steel and have furcated lower ends to spread the force exerted by the springs on the lower end of the sleeve. 

2. The mud saver apparatus of claim 1 in which the housing includes an upper and a lower section and the sleeve mounting means includes an annular member attached to the upper end of the sleeve to hold it open, said member being clamped between the upper and lower sections of the housing to hold the sleeve in place in the housing with its upper end held open by the annular member.
 3. The mud saver apparatus of claim 2 in which the resilient means includes two elongated springs positioned on opposite sides of the sleeve, each spring having one end connected to the annular member and the other end engaging the lower end of the sleeve on the opposite side thereof from the other spring.
 4. The mud saver apparatus of claim 3 in which the lower end of the sleeve is flat when closed.
 5. The mud saver apparatus of claim 4 in which the springs are made of flat spring steel and have furcated lower ends to spread the force exerted by the springs on the lower end of the sleeve. 